﻿namespace MagnusGrindalBakken.TextTools
{
    using System;
    using System.Diagnostics;
    using System.Globalization;
    using System.Runtime.InteropServices;
    using System.ComponentModel.Design;
    using Microsoft.Win32;
    using Microsoft.VisualStudio;
    using Microsoft.VisualStudio.Shell.Interop;
    using Microsoft.VisualStudio.OLE.Interop;
    using Microsoft.VisualStudio.Shell;
    using EnvDTE;

    /// <summary>
    /// This is the class that implements the package exposed by this assembly.
    ///
    /// The minimum requirement for a class to be considered a valid package for Visual Studio
    /// is to implement the IVsPackage interface and register itself with the shell.
    /// This package uses the helper classes defined inside the Managed Package Framework (MPF)
    /// to do it: it derives from the Package class that provides the implementation of the 
    /// IVsPackage interface and uses the registration attributes defined in the framework to 
    /// register itself and its components with the shell.
    /// </summary>
    // This attribute tells the PkgDef creation utility (CreatePkgDef.exe) that this class is
    // a package.
    [PackageRegistration(UseManagedResourcesOnly = true)]
    // This attribute is used to register the informations needed to show the this package
    // in the Help/About dialog of Visual Studio.
    [InstalledProductRegistration("#110", "#112", "1.0", IconResourceID = 400)]
    // This attribute is needed to let the shell know that this package exposes some menus.
    [ProvideMenuResource("Menus.ctmenu", 1)]
    [Guid(GuidList.guidTextToolsPkgString)]
    public sealed class TextToolsPackage : Package
    {
        /// <summary>
        /// An enumeration of deletion directions.
        /// </summary>
        private enum DeleteDirection
        {
            /// <summary>
            /// Represents deletion towards the left from the current point.
            /// </summary>
            Left = 1,

            /// <summary>
            /// Represents deletion towards the right from the current point.
            /// </summary>
            Right = 2,

            /// <summary>
            /// Represents deletion in both directions from the current point.
            /// Equivalent to DeleteDirection.Left | DeleteDirection.Right.
            /// </summary>
            Both = 3,
        }

        /// <summary>
        /// Default constructor of the package.
        /// Inside this method you can place any initialization code that does not require 
        /// any Visual Studio service because at this point the package object is created but 
        /// not sited yet inside Visual Studio environment. The place to do all the other 
        /// initialization is the Initialize method.
        /// </summary>
        public TextToolsPackage()
        {
            Trace.WriteLine(string.Format(CultureInfo.CurrentCulture, "Entering constructor for: {0}", this.ToString()));
        }

        /// <summary>
        /// Initialization of the package; this method is called right after the package is sited, so this is the place
        /// where you can put all the initilaization code that rely on services provided by VisualStudio.
        /// </summary>
        protected override void Initialize()
        {
            Trace.WriteLine(string.Format(CultureInfo.CurrentCulture, "Entering Initialize() of: {0}", this.ToString()));
            base.Initialize();

            // Add our command handlers for menu (commands must exist in the .vsct file)
            OleMenuCommandService mcs = GetService(typeof(IMenuCommandService)) as OleMenuCommandService;
            if (null != mcs)
            {
                // Delete current word.
                CommandID deleteWordCommand = new CommandID(GuidList.guidTextToolsCmdSet, (int)PkgCmdIDList.cmdDeleteCurrentWord);
                MenuCommand deleteWordMenuItem = new MenuCommand(DeleteCurrentWordCallback, deleteWordCommand);
                mcs.AddCommand(deleteWordMenuItem);

                // Delete word backwards.
                CommandID deleteWordBackwardsCommand = new CommandID(GuidList.guidTextToolsCmdSet, (int)PkgCmdIDList.cmdDeleteBackwardsToPreviousUppercase);
                MenuCommand deleteWordBackwardsMenuItem = new MenuCommand(DeleteWordBackwardsCallback, deleteWordBackwardsCommand);
                mcs.AddCommand(deleteWordBackwardsMenuItem);

                // Delete word forwards.
                CommandID deleteWordForwardsCommand = new CommandID(GuidList.guidTextToolsCmdSet, (int)PkgCmdIDList.cmdDeleteForwardsToNextUppercase);
                MenuCommand deleteWordForwardsMenuItem = new MenuCommand(DeleteWordForwardsCallback, deleteWordForwardsCommand);
                mcs.AddCommand(deleteWordForwardsMenuItem);
            }
        }

        private void DeleteCurrentWordCallback(object sender, EventArgs e)
        {
            if (sender != null)
            {
                DeleteWord(DeleteDirection.Both);
            }
        }

        private void DeleteWordBackwardsCallback(object sender, EventArgs e)
        {
            if (sender != null)
            {
                DeleteWord(DeleteDirection.Left);
            }
        }

        private void DeleteWordForwardsCallback(object sender, EventArgs e)
        {
            if (sender != null)
            {
                DeleteWord(DeleteDirection.Right);
            }
        }

        private void DeleteWord(DeleteDirection direction)
        {
            EnvDTE.DTE dte = this.GetService(typeof(SDTE)) as EnvDTE.DTE;
            if (dte.ActiveDocument == null)
            {
                return;
            }

            TextDocument textDocument = (TextDocument)dte.ActiveDocument.Object();
            var selection = (TextSelection)textDocument.Selection;
            var point = selection.ActivePoint;
            int lineNum = point.Line;
            int offset = point.LineCharOffset;

            if (!dte.UndoContext.IsOpen)
            {
                dte.UndoContext.Open(string.Format("DeleteWord{0}", direction));
            }

            selection.SelectLine();
            string line = selection.Text;

            int numCharsLeft = 0, numCharsRight = 0;
            if (direction.HasFlag(DeleteDirection.Left))
            {
                try
                {
                    numCharsLeft = Library.DeleteLeftToNearestUppercase(line, offset);
                }
                catch (ArgumentOutOfRangeException)
                {
                    // Not sure why yet, but this happens sometimes.
                    string warningMessage = string.Format(CultureInfo.CurrentCulture, "Delete left - out of range: line = \"{0}\", offset = {1}", line, offset);
                    System.Diagnostics.Trace.TraceWarning(warningMessage);
                    return;
                }
            }

            if (direction.HasFlag(DeleteDirection.Right))
            {
                try
                {
                    numCharsRight = Library.DeleteRightToNearestUppercase(line, offset);
                }
                catch (ArgumentOutOfRangeException)
                {
                    // Not sure why yet, but this happens sometimes.
                    string warningMessage = string.Format(CultureInfo.CurrentCulture, "Delete right - out of range: line = \"{0}\", offset = {1}", line, offset);
                    System.Diagnostics.Trace.TraceWarning(warningMessage);
                    return;
                }
            }

            textDocument.Selection.MoveToDisplayColumn(lineNum, offset);

            if (numCharsLeft > 0)
            {
                textDocument.Selection.DeleteLeft(numCharsLeft);
            }

            if (numCharsRight > 0)
            {
                textDocument.Selection.Delete(numCharsRight);
            }

            dte.UndoContext.Close();
        }
    }
}
